A random sample is obtained from a population with μ = 120 and σ = 20, and a treatment is administered to the sample. Which of the following outcomes would be considered noticeably different from a typical sample that did not receive the treatment?
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Solution:
we are given that : a random sample is obtained from a population with μ = 120 and σ = 20, and a treatment is administered to the sample.
We have to find from the following outcomes that would be considered noticeably different from a typical sample that did not receive the treatment.
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Thus we need to find z score for each :
z score formula :
Part a)
n = 36 with M = 121
b) n = 36 and M = 123
c) n = 144 and M = 121
d) n = 144 and M = 124
Thus z = 2.40 is for n = 144 with M = 124,
thus outcome d. n = 144 with M = 124 would be considered noticeably different from a typical sample that did not receive the treatment.
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